It is well known that increasing the feed consumption or intake of an animal will increase the weight, or in the case of dairy cow or lactating cow, the milk production of the animal. For example, increasing the growth and weight of the animal brings it to market weight in a shorter period of time, resulting in a substantial savings to the grower.
Although animals always have certain blood levels of growth hormone or related substances, when the growth hormone level is increased above normal, the feed intake or consumption of certain animals decreases. Therefore, it is important to increase the feed intake of these animals, such as pigs and chickens, since they suffer from a feed intake depression. We have discovered that the administration of thyroid-active substances (also including thyrotropic principles) increase the feed intake of those animals, which have above-normal or elevated blood levels of growth hormone.
When dairy cattle have above-normal blood levels of growth hormone, their milk production increases, but their feed intake does not increase nor decrease. This means that the dairy cow is producing more milk without additional feed. It is advantageous to increase the cow's feed intake and, thereby, further increase the quality and quantity of milk production. Therefore, the administration to thyroid-active substances to dairy cattle to increase feed intake is also a part of this invention.